Communicating Timely Information on the Evolving Convective Available Potential Energy (CAPE) using Geostationary and Polar Orbiting Sounders: Application to El Reno Event

A deadly EF5 tornado hit Moore, Oklahoma on May 20, 2013 killing 24 people. Two weeks later on May 31, 2013 nineteen tornados struck central Oklahoma. After hearing a forecast for these tornados, many citizens tried to escape the storm by traveling south to Texas on interstate forty. The interstate soon became traffic jammed for miles. Unfortunately, a massive and unpredictable tornado traveled across the interstate and killed a woman and child in a car near El Reno, Oklahoma in the late afternoon. The most recent prior vertical sounding information from the operational radiosonde network was at 6 am, nearly twelve hours before the tornado touchdown. There are two lessons to consider from these tragedies. One, communication strategies in this scenario need to be analyzed from not only a scientific viewpoint but also from a social perspective. Two, satellite soundings from METOP IASI at 10:30 am and Suomi-NPP CrIS at 1:30 pm combined with hourly data from the GOES Sounder have the potential of providing vertical sounding information that is both timely and accurate.

Using climatology as a guideline, we will analyze how the convective stability of the atmosphere for severe weather differs from typical days in the previous years without severe storms. We will look at the ability of satellite observations to characterize the probability distribution function of CAPE for Oklahoma in the May-June time period for the past decade. A particular focus will be on the ability of the combination of data with high vertical resolution infrared sounders on polar orbiting satellites along with a lower vertical resolution sounder in geostationary orbit to capture the extreme high tail of the CAPE probability distribution. The El Reno event will serve as a case study for showcasing satellite sounding timeliness. It is hoped that assimilation of satellite soundings into numerical models for the analysis and prediction of severe convective weather will prove to be a priority for the future. Understanding how and when satellites can be helpful in providing advance notice for severe events is important for improving the flow of timely information needed for communicating to the public.